Growing up, twin brothers Ross and Matt Duffer loved movies — especially Tim Burton's Batman. In fact, the creators of the Netflix series Stranger Things 2 credit Burton — and his over-the-top style — with inspiring them to try their hands at filmmaking.

"Tim Burton — he's not exactly a subtle filmmaker," Ross Duffer says. "I mean that in a good way. ... I remember as a kid even you can go, 'Someone is behind all of this. It's the same person who is doing Beetlejuice, who's doing Batman.'"

Beginning in the third grade, the brothers started writing, shooting and editing their own movies. Now grown, they're still at it. Their 2016 Netflix series, Stranger Things, followed a group of middle school friends who investigate supernatural goings-on in the fictional town of Hawkins, Ind.

The series was a hit, and the brothers saw the second season as a sequel, which initially worried Netflix. "Most sequels are generally disappointments," Ross says.

But the Duffers thought of Stranger Things 2 as an opportunity to expand on their show's first season. "We wanted it to feel bigger than season one," Matt Duffer says. "We wanted to scale it up a little bit."

Interview Highlights

On the success of Stranger Things

Matt Duffer: There's so much content out there in the world that the fear was you're just going to get lost. Even if people do like it, and we thought best case scenario is we're appealing to people like us who are nostalgic for this style of storytelling. So the surprise to us came when especially the younger generation started to fall in love with these characters, and then start tweeting about it and then word started to spread.

Netflix was always behind the show and they always loved it. ... What they told us is that they were hoping that word of mouth would spread, but it's going to take some time. Word of mouth is certainly what got the show its popularity, but I think everyone was taken aback by how quickly that word of mouth spread.

On auditioning over 1,000 child actors

Ross Duffer: One of our favorite things is the casting of these kids, just because it was certainly over a thousand, and some of that gets weeded out by our casting director and then otherwise you can generally tell instantly with this stuff.

You don't need to watch a full audition and debate whether this kid is right or not. ... Generally, with all of our main kids, you knew within a few seconds of them speaking, because what we're looking for is something that felt authentic, because there's this sort of Disney Channel kid, which is overdoing it. They're trying to be cute. Whereas our kids, to us, just felt there was something authentic about it. ... Once we found this group of kids, we ended up shaping the characters around them.

On the creepy plants that appear in Stranger Things 2

Matt: I found snakes creepy. That's why we have all these vines and stuff ... in season two that move and grab people. ... [In] the classic sci-fi stuff, there's always something very organic about some of the supernatural environments. ...

I was just watching the 1978 Invasion of the Body Snatchers, which is one of my favorites, and they've got those pods that shoot out these disgusting duplicates, like flower petals spewing out a baby Jeff Goldblum — it's the worst/best. I'm sure we're pulling from all that.

On co-writing screenplays together

Matt: A lot of our work is actually done on Google Docs, and so we don't speak to each other. It's a really weird thing where we're both on headphones, not talking, and just typing on the same document at the same time.

We're in the same room, same office. We have separate desks. We're not, like, literally right next to each other, because we'd probably punch each other every once in a while, so it's good there's a little bit of physical distance.

We'll get into Google Doc wars, where I type a line of dialogue or an idea for the scene — he'll delete it. I'll go write it back in — he'll delete it again. And then the headphones come off and then we actually have to have a conversation about it. So it's a little ridiculous.

Lauren Krenzel and Seth Kelley produced and edited this interview for broadcast. Bridget Bentz, Molly Seavy-Nesper and Petra Mayer adapted it for the Web.

This is FRESH AIR. I'm Terry Gross. Our guests, the Duffer Brothers, are the creators of the popular Netflix sci-fi horror series "Stranger Things." The show takes place in the 1980s in the fictional small town of Hawkins, Ind., where a group of middle school friends investigate supernatural goings-on, including interdimensional monsters and a secretive lab run by the Department of Energy. "Stranger Things" is in part an homage to the '80s pop culture that the Duffer Brothers loved as kids, like movies by John Carpenter and Steven Spielberg and the novels of Stephen King. In keeping with the sequel-filled '80s, the Duffer Brothers titled the second season of their show "Stranger Things 2."

Matt and Ross Duffer are twins who sound very much alike and tend to finish each other sentences. Before we hear the interview they recorded with FRESH AIR producer Sam Briger, let's hear a clip from the new season.

In this scene, Dr. Sam Owens is evaluating Will Byers, a boy who, in the last season, was trapped in another dimension, an evil looking place called the Upside Down. Since then, he's either having flashbacks or new encounters with the Upside Down. The doctor is played by Paul Reiser, and Will is played by Noah Schnapp.

(SOUNDBITE OF TV SHOW, "STRANGER THINGS")

PAUL REISER: (As Dr. Sam Owens) So how did you feel when you saw this storm?

SCHNAPP: (As Will Byers) No, like how you feel when you're scared and you can't breathe or talk or do anything. I felt this evil, like it was looking at me.

REISER: (As Dr. Sam Owens) It was evil? Well, what do you think the evil wanted?

SCHNAPP: (As Will Byers) To kill.

REISER: (As Dr. Sam Owens) To kill you?

SCHNAPP: (As Will Byers) Not me. Everyone else.

SAM BRIGER, BYLINE: Matt and Ross Duffer, welcome to FRESH AIR.

ROSS DUFFER: Thank you. Thanks for having us.

BRIGER: So you called the second season "Stranger Things 2," so you're clearly marking it as a sequel. You guys are such big film fans. Did you talk to each other about, like, what are the rules of sequels, and what are sequels supposed to do?

R. DUFFER: Yes, we did. And, you know, you also - I mean, but I think Netflix, when we first mentioned this - that we saw it as a sequel - got worried because most sequels are, you know, generally disappointments. And so a lot of what we did was just sort of looking at the sequels that, you know, we loved so much growing up and seeing how they succeeded and then trying our best to follow in those footsteps and not mess this thing up.

BRIGER: What were some of those sequels that you really loved?

MATT DUFFER: Oh, well, I mean, we always go to, like, James Cameron as sort of the master of it. You know, he did two of the greatest sequels of all time, which was one of - you know, a sequel to his own movie, which was "T2" - "Terminator 2."

BRIGER: And "Aliens" too.

M. DUFFER: And he also did "Aliens." And so we kind of looked at, you know, how he was able to do that. It's, like, they're arguably better than the originals. It retained a lot of the mythology of the originals and the feeling of it, but then it expanded on it in a really exciting way. So it felt like there was a reason for it to exist. And they scaled up, and that was something we talked about. We wanted to scale it up a little bit.

BRIGER: Right, more monsters.

M. DUFFER: More - I know it's the cliche. It's, like, one monster - multiple monsters. But yeah, I mean, like, there - so there's something, like, very childish about us, you know, if you get to know us. It's, like, so we wanted to do that even though we knew we'd get some flak for it. But it's, like - it's fun, and we wanted it to feel bigger, you know, than Season 1.

BRIGER: Yeah, what were you interested in expanding in the storyline?

M. DUFFER: Well, I mean, first of all, there were a lot of characters we introduced in Season 1, so we wanted to get into them a little bit more and to the - learn about who they are. We have the character of Dustin and Lucas, who were kind of, like - the people loved them last year, but we didn't get into their houses. We didn't get to meet their families. So it was, like, suddenly, you have all this additional time to explore these characters because we fell in love with these actors and what they're able to do. And, like, so you get to expand in the - on the character level. And then you also get to expand it in terms of, we wanted some of these big, spectacular, blockbuster visual effects and put those into the show. I mean, that was something I was really excited about doing, and it's something you don't often see in TV. You know, "Game Of Thrones" has been doing it, and I thought that some of that stuff is really revolutionary because you're taking these spectacular visual-effects sequences that you see in the movies, but right now, you know, in the movies, that's all you're seeing. So you don't actually care about what's happening, so your eyes are, like, really wowed, but, like, you don't feel anything. There's something soulless about it. You know, when "Game Of Thrones" applies those sort of visuals to sequences involving characters that you're really, super invested in because you've spent so many hours with them, getting to know them, then that's, like, really, really powerful. So, you know, we wanted to do some of that this year.

BRIGER: So the Upside Down is the name that the kids give this alternate universe that all these scary monsters come out of. Can you just describe it a little bit?

M. DUFFER: Yeah, I mean, we really saw it as sort of a nightmare version of our world. But as we started breaking this story and we realized we needed to go in there - but we didn't have the money to turn it into a visual effects extravaganza and we didn't - we just thought that would take you right out of the story. And so we ended up just sort of grounding it and using our locations but then just, sort of, you know adding vines on it and then adding these - a version of snow, which is these - what we called spores. And so what happens then is - this is actually a very easy thing for us to achieve, but it just sort of creates this horrific version of what already exists.

BRIGER: Yeah. It's like the town sort of got covered up with vines and these scary, plantlike things. The - oh, monsters are very plantlike. Did you find plants creepy growing up? Like, even the monsters, like, they have these mouths that, like, open up and they're, like, flower petals covered in teeth.

M. DUFFER: No, I don't have a plant problem.

(LAUGHTER)

M. DUFFER: You know, I don't. You know, it's just, like - no, I found snakes creepy. That's why we have all these vines and stuff

BRIGER: Yeah, that move.

M. DUFFER: In - yeah, in Season 2 that move and grab people and stuff. So that really bothers me. Like, I have a real snake phobia. No, but there's something gross - like, all these - like, the classic sci-fi stuff - there's always something very organic about some of the supernatural environments. I mean, "Alien" did it. That's a - like, very plantlike organisms. And then I was just watching, like, the 1978 "Invasion Of The Body Snatchers," which is one of my favorite. And they've got those pods that shoot out these, like, disgusting duplicates. They're, like, flower petals, like, spewing out, like, a baby Jeff Goldblum. It's the worst/best. So I don't - I know. I'm sure we're pulling from all of that.

BRIGER: Well, the kids are just so great in the shows. Is it true that when you were casting, you looked at a thousand auditions, and what were you looking for? And did you want to cast, like, one of the kids first or you just found one, and then it all fell into place or...

R. DUFFER: I mean, I actually - it's our - one of our favorite things is sort of the casting of these kids just because - yeah, I mean, it was certainly over a thousand. And some of that gets weeded out by our casting director. And then otherwise, you can generally tell instantly with this stuff. You don't need to watch a full audition and debate whether this kid is right or not. It was generally - with all of our main kids, you knew within a few seconds of them speaking because what you - what we were looking for is just something that felt authentic because there's this sort of - you would call it sort of, like, the Disney Channel-kid, which is, they're just overdoing it. They're, like, trying to be cute, whereas our kids all, to us, just felt - there was just something authentic about it. I remember Finn Wolfhard, who plays Mike, was just - he was, like, sick when he filmed his audition. And he was just, like, lying on the bed, and his dad filmed him with his crappy phone, and it just looked terrible. But it didn't matter because it just felt real. And even though Finn wasn't how we imagined Mike at all originally - he has much more of a manic, fidgety energy than we ever expected for Mike, but it doesn't matter. Once we found this group of kids, we then ended up shaping the characters around them.

BRIGER: What were you guys like as kids? Did you have a close-knit group of friends like this?

R. DUFFER: We did, especially through, you know - in elementary and middle school. And our best friend that lived right next door to us - you know, every summer we would make a movie together. He would be our co-director and co-writer. And we didn't really write. It was more like rough outlines that then we'd improv together but - and, you know, then we would get all of our friends together, and we would make these movies. So a lot of "Stranger Things" is actually pulling from that and just trying to recapture a bit of what those summers felt like because even though we weren't fighting monsters or discovering telepathic girls, we - it...

M. DUFFER: In our heads, we were.

R. DUFFER: Well...

M. DUFFER: I mean, that - we were imagining all of that.

BRIGER: That's what you're hoping for, probably.

M. DUFFER: Yeah, yeah, yeah.

R. DUFFER: We were hoping for, like, these big adventures. And yes, are we referencing "Stand By Me" when we have our characters walking down train tracks? Yes, but also, we were walking down train tracks as kids. And so, you know, a lot of it is trying our best to recapture those summer childhood experiences.

GROSS: We're listening to the interview FRESH AIR producer Sam Briger recorded with the Duffer brothers, the creators of the Netflix series "Stranger Things." The second season, "Stranger Things 2," is now streaming on Netflix. They'll talk more after a break. This is FRESH AIR.

(SOUNDBITE OF DANILO PEREZ AND CLAUS OGERMAN'S "THE SAGA OF RITA JOE")

GROSS: This is FRESH AIR. Let's get back to the interview FRESH AIR producer Sam Briger recorded with the Duffer brothers, Matt and Ross Duffer, who created the Netflix sci-fi horror series "Stranger Things." It's about a group of middle school friends investigating supernatural goings on.

BRIGER: You know, monsters aside, the kids in your show are going through some really tough times in terms of - they're going through adolescence.

R. DUFFER: Yeah.

BRIGER: I mean, and they're - it's an incredibly intense time. They're dealing with their first crush. That's testing their friendships. People are moody, and they're jealous. They're pulling away from their parents. I think you really capture that really well. Did you have a good sense memory of how fraught those times were?

M. DUFFER: I just remember being incredibly insecure, you know, especially moving into high school, being extremely anxious, not really knowing...

BRIGER: Just socially, or...

M. DUFFER: Socially, yeah. I mean, we were socially - we struggled a lot. And it started out because - it started out even really, really young, like, 'cause we wouldn't hang out with anyone aside from each other. Like so it was only just me and Ross. And you know, the teachers got concerned because they were like, we weren't developing the proper social skills to function in society, basically. It was like, they're not prepared to function.

So we were actually - we - they were like, they need to repeat kindergarten, which we did. So I've been behind a year my entire life, which always made me feel weird. We're twins. There are a lot more twins now. When we were growing up in North Carolina, there were no twins. And everyone's like, it must be so great to be a twin. But I hated it because it was like, even though I loved my brother and our - you just - it made you feel weird and different and like you didn't fit in. And really, when you're that age, all you want to do is fit in.

BRIGER: You guys are making movies, like, starting in third grade.

M. DUFFER: Yeah.

BRIGER: I think the first one was based on a card game called Magic the Gathering, which is kind of like a second- or third-generation D&D kind of game in terms of, like, fantasy.

R. DUFFER: Right.

M. DUFFER: Yeah.

BRIGER: So you would get your friends to star in these roles, and then you have some big production valued pieces (laughter).

M. DUFFER: I mean, we didn't have another actor, so we would also act.

R. DUFFER: And editing is more than anything what started to teach us how to be filmmakers - that you can shoot a scene. I mean, it was very crude and basic. But to us, it really altered our little films - which is, you can film a scene multiple times, and then we can splice this together. And then we can put the music underneath. And suddenly our projects became much more sophisticated. And so...

M. DUFFER: By that, he means watchable.

BRIGER: Watchable.

M. DUFFER: Yeah.

(LAUGHTER)

M. DUFFER: I will say, though, that there was one moment where, you know, we flirted with popularity in high school, which was when people realized that our videos, if used for a class assignment, would get you an automatic A.

BRIGER: (Laughter).

M. DUFFER: And so it took me, like, a few months to realize I was just being used. They would only hang out with us while we were making the film for them. And then they would - once they got their A, then I would never hear from them again until they needed another video. And at some point, I was like, why am I doing this?

R. DUFFER: I remember it was - I got a call from a cool kid, and he's like, we're - for history class, we want to, you know, film the storming of Normandy.

(LAUGHTER)

R. DUFFER: And I was like, OK, 'cause "Saving Private Ryan," you know, had been out recently. I was like, OK, when do you want to do this storming of Normandy? And they were like, this afternoon at Jordan Lake. And so I was like, well, I guess I should hang out with the cool kids. So I went out there with our camera and...

M. DUFFER: Yeah. I wasn't there, actually.

R. DUFFER: No, and we - I just, I was like - you know, I adjusted the colors on the camera. And I adjusted the shutter speed. And I just shook it a lot. And these kids are coming with their, like, squirt guns in rafts. But I shook the camera a lot. And then when I got back and put in my - into iMovie, I just - and I ripped the sound effects from "Saving Private Ryan," which really is like a huge part of the - I mean, those are Oscar-winning...

BRIGER: Yeah. That's a great sound.

R. DUFFER: ...Effects.

M. DUFFER: Some of the best sound design ever, actually.

R. DUFFER: And if you put that with shaky camera of kids, like, suddenly this thing came alive. I mean, they - for 10 years, history class still showed that project. I'm sure maybe now they've stopped, but for a while...

M. DUFFER: Why would they have stopped now?

R. DUFFER: But that was the catalyst for then, after that, every weekend we had to film a movie for people just 'cause it's really all "Saving Private Ryan's" fault. It made us look better than we were.

BRIGER: All right, so you made a movie in 2015, "Hidden," and you wrote a few episodes of the show "Wayward Pines." But, you know, "Stranger Things," being in charge of your own multimillion-dollar movie, seems like a huge step forward. When you got on the set, did you feel like you were over your head at some point?

M. DUFFER: Yeah.

R. DUFFER: It was...

M. DUFFER: Always, always.

R. DUFFER: Not as over the head as on our first movie, which was just - that was - felt like you're just being thrown into the deep end. It was more like that experience was so traumatizing for us and we were so nervous going on to "Stranger Things," it was less about running the set and more about getting it finished in time. My least favorite thing about filming is that you're always running out of time. You never have time to get it right. You never have time to do as many takes is you want, to get the scene just right. So it's always from the second you step on set, you're just - you're racing.

M. DUFFER: And like, I remember at our first movie - I guess we were 27. You know, and then you're like on this multimillion-dollar Warner Brothers movie with movie stars and stuff. And you need to convince people that you know what you're doing, but you don't totally know what you're doing. And I think that because of that you have this thing called playback, which we don't have on "Stranger Things," by the way, just to protect ourselves. But most movies and most TV shows have playback where you can - you know, once you shoot a scene, you can watch it. You can watch what you just did.

BRIGER: You said that you don't have playback on the set of "Stranger Things" to protect yourself. So what do you mean?

M. DUFFER: So we have so little time on "Stranger Things" that if you're unsure whether you got something or not, by the time you watch to check whether you had it, you could have just shot it again.

BRIGER: So you just shoot it again?

M. DUFFER: So you just shoot it again.

R. DUFFER: And the beauty of digital - and some people complain about it that it's hurting sort of discipline on film sets, which I can understand that. But especially in something with kids is we don't even have to cut the camera. We just go, go again. Go again just one more time. Say this line one more time. And then just say, say douche bag or just whatever it is. And then - and that can help sort of get the energy up of a scene. And then you're just like, OK, we got it - moving on.

M. DUFFER: But usually you can't just shout at actors off-screen, or they get really irritated at you.

R. DUFFER: (Laughter) That's true.

M. DUFFER: Like I can't shout at Winona. Like, Winona, do it again but this way. With kids, you can shout at them from off-screen. They won't get offended. You can literally grab them and move them if they're not on their mark. You know, if they're not where they're supposed to be, you can physically move them. You know, you can't do that with David Harbour. You cannot do that with Winona without getting smacked.

BRIGER: So how do you guys work together? Do you split up the writing and directing, or is it all collaborative? Do you feel like one of you is better - like Matt's better at writing dialogue and Ross is better at writing plot, or...

R. DUFFER: We usually get annoyed at each other when we answer these questions.

M. DUFFER: Yeah, yeah.

R. DUFFER: I'm like, I'm better at this. And you're like, wait a minute. You really think that? So that I may dodge. But I think that the benefit of two - you're really working as one voice when you're on set because most of the decisions that we're making comes in the writing. And so on set, it's just executing it, whereas the writing is - you know, it's very collaborative as we're breaking story and breaking outlines with each other and other writers. But then as we're writing scenes, you know, we each write a scene separately. We pass it to each other. Someone - the other one does a pass, and we pass it back. I don't think we'd be able to do this otherwise. It speeds everything up dramatically - times two.

M. DUFFER: But the funny thing is to write scripts you use this program Final Draft. You're not able to be on there at the same time. So a lot of our work is actually done on Google Docs. And so we don't speak to each other. It's a really weird thing where we're, like, both on headphones, not talking and just typing kind of on the same document at the same time. And sometimes we'll get in, like, little Google Docs wars where, like...

BRIGER: Are you seated next to each other? Are you in the same office?

M. DUFFER: Oh, we're...

R. DUFFER: In the same room.

M. DUFFER: ...In the same room - in the same office. Desks - we have separate desks. We're not, like, literally right next to each other because then we'd probably punch each other every once in a while. So it's good there's a little bit of physical distance. But we'll get into, like, Google Docs wars - you know what I mean? - like, where I type a line a dialogue or an idea for the scene. He'll delete it. I'll go write it back in. He'll delete it again. And then the headphones come off, and we get into - then we actually have to have a conversation about it. So it's a little ridiculous.

BRIGER: So when Netflix released Season 1, were you surprised by the success and the popularity of the show?

M. DUFFER: Oh, yeah.

R. DUFFER: For sure, yeah. I mean, there's so much content out there in the world that the fear was you're just going to get lost even if people do like it. And then we thought best-case scenario, though, is you were appealing to people like us that are nostalgic for this style of storytelling. So, you know, the surprise to us came when - especially, you know, the younger generation started to fall in love with these characters and start tweeting about it. And then word started to spread.

I mean, Netflix was always behind the show, and they always loved it. But what they thought and what they told us is that, you know, they were hoping that word of mouth would spread, but it's going to take some time. That was sort of what it was. And word of mouth certainly is what got the show its popularity, but I think everyone was taken aback by how quickly that word of mouth spread.

BRIGER: That's great.

M. DUFFER: So, yeah, no, it's exciting. But it's exciting now. Like, the most exciting thing I'm seeing is that people are discovering the show who hadn't - you know, who had never watched it in the first place. They're, like, starting to get annoyed about hearing about it. And they're like, fine, I guess I'll watch it...

R. DUFFER: Right.

M. DUFFER: ...Which is great. You know, I mean, that's what happened with "Game Of Thrones." I mean, "Game Of Thrones" was something that's like - it's just - fine. You know, I hate dragons. And I would never watch anything like this, right? And then they watched it, and they ended up falling in love with the characters and the world. So, you know, you want someone who's like, I find kids annoying. I don't like monsters. I don't watch anything sci-fi. And then suddenly they're watching it.

R. DUFFER: That's the hope.

M. DUFFER: That's the hope. That's the goal.

BRIGER: Matt and Ross Duffer, thanks so much for being on the show.

R. DUFFER: Oh, thank you. This is great.

M. DUFFER: Yeah, thanks for having us.

GROSS: The Duffer Brothers created the Netflix series "Stranger Things." They spoke with FRESH AIR producer Sam Briger. After we take a short break, Maureen Corrigan will review the new novel by Louise Erdrich. This is FRESH AIR.